💡 Drawback Formulation: In numerous programming duties, we could also be required to type a listing of strings not solely based mostly on alphabetical order but additionally by the size of every string.
Suppose we have now a listing of strings like ["banana", "apple", "cherry", "blueberry"].
We wish to manage this listing in order that it’s sorted by the size of every string and, for strings of the identical size, type them alphabetically.
The specified output for this listing could be ["apple", "banana", "cherry", "blueberry"].
For those who solely wish to type by size, try my article right here:
👉 Python Type Listing of Strings by Size
Methodology 1: Utilizing a Customized Sorting Perform
Python’s type() technique can take a customized sorting operate by its ‘key’ parameter. This operate is usually a lambda operate that returns a tuple the place the primary factor is the size of the string, and the second is the string itself, establishing a form precedence.
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Right here’s an instance:
fruits = ["banana", "apple", "cherry", "blueberry"] fruits.type(key=lambda merchandise: (len(merchandise), merchandise)) print(fruits)
This code snippet types the listing of fruits by size after which alphabetically. The lambda operate returns a tuple the place the primary factor is the size of the string, guaranteeing major sorting by size, and the second factor is the string, which types the same-length strings alphabetically.
Methodology 2: Utilizing the sorted() Perform with a Customized Key
The sorted() operate in Python works equally to the type() technique however returns a brand new sorted listing. You possibly can present a key operate that, once more, returns a tuple, first of the size, then the string itself.
Right here’s an instance:
fruits = ["banana", "apple", "cherry", "blueberry"] sorted_fruits = sorted(fruits, key=lambda merchandise: (len(merchandise), merchandise)) print(sorted_fruits)
On this code snippet, the listing of fruits is sorted by size and alphabetically with out altering the unique listing, because the sorted() operate creates a brand new sorted listing. The customized key operate operates the identical approach as in Methodology 1.
Methodology 3: Utilizing an Inline Perform Definition
As an alternative of a lambda, you possibly can outline an inline operate utilizing def, which may enhance readability when the sorting standards are advanced or if you happen to’re avoiding lambda capabilities for stylistic causes.
Right here’s an instance:
fruits = ["banana", "apple", "cherry", "blueberry"]
def sort_key(merchandise):
return len(merchandise), merchandise
fruits.type(key=sort_key)
print(fruits)
The code snippet above defines a sorting key operate sort_key that returns a tuple based mostly on the string’s size after which the string itself. The type() technique types the listing in-place utilizing this operate.
Methodology 4: Utilizing Operator.itemgetter for Combined Sorting
For circumstances the place you’re sorting objects or tuples and never simply strings, operator.itemgetter might be helpful. It may be utilized in mixture with sorted() or type() to type the strings by size after which alphabetically if you happen to first convert strings to tuples containing their size.
Right here’s an instance:
from operator import itemgetter fruits = ["banana", "apple", "cherry", "blueberry"] tuples = [(len(fruit), fruit) for fruit in fruits] sorted_tuples = sorted(tuples, key=itemgetter(0, 1)) sorted_fruits = [fruit for _, fruit in sorted_tuples] print(sorted_fruits)
This snippet first converts the fruit strings into tuples of (size, string), types the listing of tuples, after which extracts the sorted strings. itemgetter(0, 1) specifies the tuple indices by which to type.
Bonus One-Liner Methodology 5: Combining sorted() and Listing Comprehension
For those who fancy one-liners, you possibly can mix sorted() with a listing comprehension to attain the identical outcome, albeit much less readable for some.
Right here’s an instance:
fruits = ["banana", "apple", "cherry", "blueberry"] print([fruit for _, fruit in sorted((len(fruit), fruit) for fruit in fruits)])
This advanced one-liner creates a generator that produces tuples (size, string), types them, after which extracts the second factor of every tuple to kind the sorted listing of strings.
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